My daughter does not speak to me the way she used to

Dear Delyara, She is seventeen, and every conversation with her now feels like I am walking toward a closed door and pretending not to notice. I ask simple things and get one-word answers. I try to joke and she looks irritated. I ask how school was and she says “fine” in that flat way that means do not ask me again. Last week I found out from someone else that she had been crying in the school toilets because of a problem with her friends. She never told me. That hurt me more than I can say. I am her mother. I carried her. I stayed up with her fevers. I held her when she had nightmares. I know children grow up and become private. I know that. But nobody tells you how painful it is when your own child slowly becomes a person who no longer brings her pain to you first. Now every evening I am guessing. Is she quiet because she is tired, because she is sad, because she is angry, because she hates me, because she is just seventeen? I live in that confusion every day. And the worst part is, the more rejected I feel, the more careful I become around her, and the more careful I become, the less natural our conversations feel. I can feel something slipping, and I do not know how to hold it.